GLOSSARY. 



261 



ping of water on the floors of caverns, and having their 

 points upwards. 



Twilight, the light at the close of day after sunset and before 

 dark. 



Tortuous, crooked, convoluted. 



Tertiary, a series of sedimentary rocks, lying above the pri- 

 mary and secondary, and having characters which distin- 

 guish them from these two classes. 



Trachyte, a variety of lava essentially composed of greenstone : 

 it frequently contains detatched crystals of feldspar, and 

 sometimes hornblende and augite. 



Titaniferous, an iron ore containing titanium. 



Talc, a species of magnesian earth, consisting of smooth shining 

 lamina, translucent or transparent. * 



Transparent, admitting rays of light to pass through. 



Transverse, crosswise, across. 



Terrestrial, belonging to, or pertaining to the earth. 



Tillage, includes all mechanical operations on the soil. 



Tropical, belonging to the tropics. 



Torrid zone, the hot country included between the Tropic of 

 Cancer, and the Tropic of Capricorn. 



Tornado, a high wind, a whirlwind. 



Theory, an exposition of the principles of any science; the 

 science without the art or practice. 



Tissue, connection or organization, the proper substance of an 

 organ. 



Terminal, situated at the end. 



Thyrse, a loose irregular bunch of flowers. 



Tenacity, toughness, having strong cohesion, 



Tap root, the main root, the axis. 



Tuber, a fleshy knob or tumor on a rcot. 



Trifolium, the genus of plants to which clover belongs. 



Ternate, leaves which are arranged in threes are called ter- 

 nate. 



